Many major urban health exposures are shaped outside hospitals. Transport affects air pollution, injury risk and opportunities for activity; housing affects heat, overcrowding and security; land-use decisions influence access to jobs, food and green space. Treating each outcome separately can hide their shared policy causes.
A health-impact assessment can reveal these connections before investments are fixed. It should examine distribution, not only citywide averages, because benefits and burdens may fall on different groups. Cross-sector work is difficult when budgets and accountability remain separate, so implementation needs shared indicators and clearly named responsibilities. Connected urban policies need connected accountability. Early assessment is most useful while transport routes, housing standards and land use investments can still be changed through public decisions. At that stage, alternatives remain open.